Population changes of the itch mite, Psorergates ovis, after shearing

Authors: Gibson AJF, Sinclair AN
Publication: New Zealand Veterinary Journal, Volume 23, Issue 1-2, pp 14, Jan 1975
Publisher: Taylor and Francis

Animal type: Livestock, Production animal, Ruminant, Sheep
Subject Terms: Inflammation, Integument/skin/wool/hair/fur/feather, Disease/defect, Parasites - external, Harvesting/processing
Article class: Correspondence

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Abstract: Graham (1943) described the skin scraping technique to observe P. ovis on infested sheep. He scraped an area approximately 5 x 5 cm using light mineral oil to collect skin debris and mites. Live mites appeared opaque, but dead ones were translucent. He was able to demonstrate facilitation of mite transfer from infested to clean sheep when both were machine-shorn and held close together, as occurs in the counting-out pens after shearing. This period of likely transfer has been accepted by several observers. Murray (1961) used a larger skin scraping (10 x 10 cm) when determining the life cycle of P. ovis by transferring gravid female mites to clean sheep. He noted the appearance of larvae by day 11, protonymphs by day 20, deutonymphs by day 20, tritonymphs by day 27 and adult males by day 35. Downing and Mort (1962) observed a loss of 80% or more of the mite population on machine-shorn sheep exposed to high temperatures and sunlight, but it is not clear how they calculated this figure…

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